1. Field of the Invention
The invention relates to a lath grating for supporting mattresses or the like. The lath grating includes a frame with frame legs and a plurality of laths which are arranged parallel to one another. Vertical support shafts are arranged at both ends of the lath. The supporting shafts are connected with the laths in an articulated manner and are received by vertical guide bore holes provided in a row on the upper side of the frame legs which extend in longitudinal direction of the lath grating. Longitudinally extending chambers are cut out in the frame legs. Means for supporting the supporting shafts in a spring-like manner and which include inflatable tube-like bellows are provided in the chambers.
2. Description of the Related Art
In a lath grating construction of this kind described in German Offenlegungsschrift 38 27 476, the supporting shafts of the laths contact an endless, tensioned belt which is guided around a plurality of rollers. An inflatable bellows is provided below the belt for tensioning same, which bellows directly contacts the underside of the endless belt. This bellows lies in a longitudinally extending rectangular chamber. The tensioning of the endless belt which is guided over rollers is to be regulated by means of this bellows. This construction is not advisable for several reasons: in terms of construction it requires a large overall height because the endless belt, which is guided over rollers, and the bellows are arranged one above the other; the construction cost in this case is high because of the rollers and the endless belt; the softness which can be achieved in principle by an air suspension and the support which can be regulated to a great extent are canceled out by the circumferentially extending belt, so that this previously known construction as a whole is not advisable.
A lath grating whose frame sides are constructed as channel-like grooves is known from U.S. Pat. No. 4,525,886, wherein the side pieces which laterally define these channel-like grooves comprise vertical slots. Tubes are placed in the two channel-like grooves. The ends of the laths of the lath grating carry laterally projecting bearing journals which are placed in open grooves of bearing shells. The bearing shells, in turn, are placed on the tubes. A tube consisting of a very rigid material with little elasticity must be used in this case, so that the tube which is loaded and under pressure is not squeezed up between the bearing shells which succeed one another at intervals. Accordingly, the softness which is achievable, per se, by air suspension and the easy adjustability of the support are negated by the hard material of the tube which must necessarily be used in this case.
European Patent 116 237 and European Application 161 392 also show and describe a lath grating. These known lath gratings comprise two tube-like bellows which lie parallel to one another and at a distance from one another horizontally; at the upper side of the latter are fastened flat strips extending along the bellows which comprise pocket-like recesses in which the ends of the laths forming the lath grating are inserted. The entire width of the individual laths directly contacts the aforementioned bellows and, as tests have shown, the spring characteristic of this construction is considerably impaired by the large support surface of these laths.
The springing suspension and support of the laths of the lath grating would be ideal if every supporting shaft were constructed as a piston-cylinder unit, wherein all of these piston-cylinder units would communicate with one another pneumatically. Such a solution has already been proposed in German Offenlegungsschrift 38 27 476, but the construction cost involved is much too high and the construction is accordingly too expensive, so that such a suggestion has thus far not been put into practice.